The invention refers to an adapter for memory cards. More precisely, it refers to an adapter allowing to connect a second device to a memory card port in addition to a memory card.
The market for memory cards has grown significantly based on the possibility of storing large amounts of data on Flash cards. There are different standards for such memory cards, for instance the SD standard (Secure Digital). Like all standards for memory cards, the SD standard defines a card format, a connector type and a protocol of communication between the host device designed to take up the SD card, as well as the card itself. The SD standard as used in this document refers to publications of the SD Card Association, including specifications of “SD memory card, Physical layer specification”, “SDHC memory card”, “miniSD card”, “microSD card”, “SDIO card” and “SD host controller specification”. Furthermore, certain memory card standards use an extended communication protocol which allows to use additional instructions for using different devices than memory cards. In particular, the SD standard includes an extended command set called SDIO (Secure Digital Input Output device). With this SDIO extension, one can connect different input/output devices to the host.
Within the realm of SD, it is common to use SDIO type cards to allow other services than just data storage. This is also known as SD-MCE (Secure Digital-Mobile Commerce Extension). With this card, one can implement other services than just memory storage, for instance pay TV, on mobile devices such as mobile phones or portable computers.
However, mobile devices usually only have one such memory card port, and a second port for such devices is not expected in the future. This means that a user who wants to use pay TV on their phone cannot use a memory card at the same time. Changing the cards as needed is not a good solution because the memory card is not available while the TV function is being used. Users might want to store data while using the TV function. The SD standard is not designed to allow the parallel connection of two devices at one single port at the same time.
The invention consists of an adapter allowing to connect two electronic devices at the same port, at the same time. Thus the host device communicates with one single device, allowing to implement an electronic function on one side while using the storage device on the other side. More generally, the invention constitutes a solution to actuate two devices at one single port which originally allows the connection of only one device.
This means that the invention is an adapter including a primary connector, a secondary connector, an interrupter and a device interface circuit. The primary connector is connected with the host taking up said adapter device. The second connector is taking up a memory card. The interrupter links the primary connector and the secondary connector. The device interface circuit is connected to the primary connector and controls the opening or closing of the interrupter depending on the commands received by the first connector.
The invention preferably includes an application circuit connected to the device interface circuit. The adapter includes a host interface circuit connected to the secondary connector for communication with the memory card. The device interface circuit and the host interface circuit are interconnected to exchange data and determine common features while taking the features of the card and the own features of the device into account.
In accordance with a special way of carrying out the invention, the device interface circuit closes the interrupter when a command is received by the primary connector and keeps it closed to let the response from the card pass if the command is directed toward the card. If no card is connected, the device interface circuit reacts to all commands. The device interface circuit closes the interrupter when a command is received by the first connector and opens the interrupter to block the response from the card if the command is directed toward the application circuit.